| Value | Category | Cases | |
|---|---|---|---|
| 2008 | 1 |
20%
|
|
| 2013 | 2 |
40%
|
|
| 2014 | 1 |
20%
|
|
| 2015 | 1 |
20%
|
|
| 9998 | don't know | 0 |
0%
|
| Sysmiss | 38713 |